Couple things I've heard from people:
Originally Posted by lexiem
1) The people who just want a long form for Lily. Or say "but Lily is so popular" and don't really know much of anything about Lilith. I've heard it spun as a less-popular Lillian and not as sweet as Lilibet. This isn't really my association but I've heard it a few times and I found it interesting.
2) Some (Masorti or Reform mostly, not Orthodox) Jewish people regard Lilith as a bit of a feminist or at least multi-faceted character. That was my formative encounter with Lilith, Adam's first wife who would not be subservient to him.
It's been on my list for ages. And I'm not the sort of person that would use Jezebel or Delilah. Delilah's doing pretty well on the charts but it's never been palatable to me.